The present invention relates to a catalyst comprising a carbon support and platinum and two other metals thereon, especially to a platinum alloy catalyst employed as an electrocatalyst of a fuel cell.
Catalysts consisting of a carbon support and various catalyst metals chiefly including platinum supported thereon have been heretofore employed as electrocatalysts for various chemical reactions and fuel cells. Further, in order to elevate the catalytic performance, other metals such as nickel and chromium are supported on the support in addition to the platinum.
However, the activities of these platinum-containing catalysts for the various reactions are not satisfactorily high (U.S. Pat. No. 5,079,107) so that a catalyst having higher activities, and preferably a longer life is desired.
U.S. Pat. No. 4,985,386 of Tsurumi et al. discloses carbon-supported platinum catalysts containing at least one other metal, including a combination of platinum, iron and manganese. The catalysts of the patented invention are all carburized to form carbides of at least some of these metals, and firmly fix the metals to the carbon supports. Although several examples and comparative examples (uncarburized catalysts) are provided, the combination of platinum, iron and manganese is not exemplified in either form.